This disclosure relates to vehicle telematics, with a particular emphasis on devices, systems, and methods for remotely controlling vehicle systems. Radio-based key fobs can send commands to vehicles wirelessly, for example, to lock or unlock the doors. In recent years, key fobs have also included remote start capabilities. However, the range of radio-based key fobs is limited to the vehicle's immediate area.
Many vehicles are now equipped with telematics systems in which digital data is communicated both to and from the vehicle. With these systems, it is possible to send remote commands over data networks. In a typical telematics system, a data communications module (DCM) in the vehicle is configured to transmit or receive data using a cellular or other type of mobile network. The DCM is equipped with an address or identifier unique to the vehicle (akin to the vehicle's own cell phone number). Because the telematics system is designed to operate over a mobile network, the DCM may need to be configured to conform to that network's communications protocols. For example, some DCMs are configured to accept messages based on the SMS (short message service) protocol employed by many mobile networks worldwide.
In some manufacturers' telematics systems, a central data center communicates with all DCMs worldwide. However, vehicles at various locations worldwide will necessarily be connected to a variety of local or regional mobile networks. Moreover, there may be telematics providers serving as intermediaries between the data center and each mobile network (for example, a different telematics provider may be employed in each different country or region). Accordingly, the communication path from the data center to a DCM in a vehicle located somewhere in the world may involve many steps as the data moves from one network to another or from one network provider to another. This multi-stage process can add many seconds to the data transmittal, which could cause a driver who sends, for example, a remote start command from a mobile device to have to wait before the command reaches the vehicle and is executed.